This description relates to power supplies, and, more particularly, to methods and systems for a medium voltage battery backup uninterruptible power supply.
Uninterruptible power supplies (UPS) are used in many applications such as in data centers and hospitals to provide quality power to the load without any interruption even when there are outages or disturbances in the AC mains supply voltage. As the size of data centers increase, powering up the critical loads through a low voltage (e.g. 480 V) UPS is a challenge as the current magnitude increases significantly as the power requirement increases at that relatively low voltage, even hitting the limits of the low voltage switchgear. Processing the required power at a relatively higher voltage, such as medium-voltage (e.g. 4.16 KV or 13.8 kV) allows the current carrying requirement of the UPS to decrease. Thus, medium voltage conversion in the UPS (e.g. 4.16 kV or 13.8 kV) has advantages with respect to increased operating efficiency and reduced cabling cost. Moreover, switch components such as insulated-gate bipolar transistors (IGBT) degrade over time at near rated voltage and current. Operating higher voltage rated IGBTs at lower current may also improve reliability of the components in the UPS.